We have engaged in a series of studies to evaluate the long term safety and potential therapeutic activity of humanized anti-IL-2 receptor monoclonal antibody (Daclizumab) therapy in the treatment of patients with severe, sight-threatening, intermediate and posterior non-infectious uveitis. This was based on our initial observations in an animal model for human uveitis. Our initial study in patients was a non-randomized, open-label study to evaluate the long term safety and potential therapeutic activity of daclizumab. In that study, patients with chronic, non-infectious bilateral, sight-threatening uveitiswere weaned off their immunosuppressive agents according to a standardized schedule, while ultimately receiving Daclizumab infusions every 4 weeks. Anti-Interleukin 2 receptor antibody therapy appeared to prevent the expression of severe sight-threatening intraocular inflammatory disease in most patients, based on the primary end point of a loss of vision of 10 letters or more from baseline in either eye. All patients were able to tolerate the study medications without the need for dose reduction. Some patients at one year of therapy were randomized to therapy intervals of 6 weeks, with most of those receiving therapy at 6 week intervals having recurrences of their disease. 7/10 Patients have now received anti-IL2 receptor therapy for up to 4 years. No apparent increase in the infection rate has been seen in these patients. Those patients were converted to monthly subcutaneous administration of the medication instead of infusions. Patients have tolerated this transition with no problems. Based on these findings we have initiated a second study. : Fifteen study participants with sight-threatening uveitis quiescent on immunosuppressive therapy were enrolled at 3 sites and treated with subcutaneous daclizumab, 2 mg/kg every 2 weeks x2, then maintenance at 1 mg/kg every 2 weeks, with simultaneous tapering of the standard immunosuppressive therapy.Treatments were well tolerated and 11/15 patients reached the preset outcome by eliminating 50% of their standard immunosuppressive medications by 12 weeks without recurrence of their ocular inflammatory disease or reduction in visual acuity. Of the 10 participants that have completed 6 months of followup, 9 were able to reduce or maintain 50% of their baseline medication load without significant loss of vision or increase in disease activity. A study was performed in a small number of patients who had active uveitis in spite of standard immunosuppressive therapy. All the patients' disease responded to the administration of high dose (8mg/kg followed by 4mg/kg) therapy. We are evaluating this data. Discussions continue at developing a Phase III study. As well, a new protocol to explore the possibility of treating active uveitis with this medication will start shortly.